1 /* 2 * f_loopback.c - USB peripheral loopback configuration driver 3 * 4 * Copyright (C) 2003-2008 David Brownell 5 * Copyright (C) 2008 by Nokia Corporation 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 */ 12 13 /* #define VERBOSE_DEBUG */ 14 15 #include <linux/slab.h> 16 #include <linux/kernel.h> 17 #include <linux/device.h> 18 #include <linux/module.h> 19 #include <linux/err.h> 20 #include <linux/usb/composite.h> 21 22 #include "g_zero.h" 23 #include "u_f.h" 24 25 /* 26 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals, 27 * 28 * This takes messages of various sizes written OUT to a device, and loops 29 * them back so they can be read IN from it. It has been used by certain 30 * test applications. It supports limited testing of data queueing logic. 31 */ 32 struct f_loopback { 33 struct usb_function function; 34 35 struct usb_ep *in_ep; 36 struct usb_ep *out_ep; 37 38 unsigned qlen; 39 unsigned buflen; 40 }; 41 42 static inline struct f_loopback *func_to_loop(struct usb_function *f) 43 { 44 return container_of(f, struct f_loopback, function); 45 } 46 47 /*-------------------------------------------------------------------------*/ 48 49 static struct usb_interface_descriptor loopback_intf = { 50 .bLength = sizeof(loopback_intf), 51 .bDescriptorType = USB_DT_INTERFACE, 52 53 .bNumEndpoints = 2, 54 .bInterfaceClass = USB_CLASS_VENDOR_SPEC, 55 /* .iInterface = DYNAMIC */ 56 }; 57 58 /* full speed support: */ 59 60 static struct usb_endpoint_descriptor fs_loop_source_desc = { 61 .bLength = USB_DT_ENDPOINT_SIZE, 62 .bDescriptorType = USB_DT_ENDPOINT, 63 64 .bEndpointAddress = USB_DIR_IN, 65 .bmAttributes = USB_ENDPOINT_XFER_BULK, 66 }; 67 68 static struct usb_endpoint_descriptor fs_loop_sink_desc = { 69 .bLength = USB_DT_ENDPOINT_SIZE, 70 .bDescriptorType = USB_DT_ENDPOINT, 71 72 .bEndpointAddress = USB_DIR_OUT, 73 .bmAttributes = USB_ENDPOINT_XFER_BULK, 74 }; 75 76 static struct usb_descriptor_header *fs_loopback_descs[] = { 77 (struct usb_descriptor_header *) &loopback_intf, 78 (struct usb_descriptor_header *) &fs_loop_sink_desc, 79 (struct usb_descriptor_header *) &fs_loop_source_desc, 80 NULL, 81 }; 82 83 /* high speed support: */ 84 85 static struct usb_endpoint_descriptor hs_loop_source_desc = { 86 .bLength = USB_DT_ENDPOINT_SIZE, 87 .bDescriptorType = USB_DT_ENDPOINT, 88 89 .bmAttributes = USB_ENDPOINT_XFER_BULK, 90 .wMaxPacketSize = cpu_to_le16(512), 91 }; 92 93 static struct usb_endpoint_descriptor hs_loop_sink_desc = { 94 .bLength = USB_DT_ENDPOINT_SIZE, 95 .bDescriptorType = USB_DT_ENDPOINT, 96 97 .bmAttributes = USB_ENDPOINT_XFER_BULK, 98 .wMaxPacketSize = cpu_to_le16(512), 99 }; 100 101 static struct usb_descriptor_header *hs_loopback_descs[] = { 102 (struct usb_descriptor_header *) &loopback_intf, 103 (struct usb_descriptor_header *) &hs_loop_source_desc, 104 (struct usb_descriptor_header *) &hs_loop_sink_desc, 105 NULL, 106 }; 107 108 /* super speed support: */ 109 110 static struct usb_endpoint_descriptor ss_loop_source_desc = { 111 .bLength = USB_DT_ENDPOINT_SIZE, 112 .bDescriptorType = USB_DT_ENDPOINT, 113 114 .bmAttributes = USB_ENDPOINT_XFER_BULK, 115 .wMaxPacketSize = cpu_to_le16(1024), 116 }; 117 118 static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = { 119 .bLength = USB_DT_SS_EP_COMP_SIZE, 120 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 121 .bMaxBurst = 0, 122 .bmAttributes = 0, 123 .wBytesPerInterval = 0, 124 }; 125 126 static struct usb_endpoint_descriptor ss_loop_sink_desc = { 127 .bLength = USB_DT_ENDPOINT_SIZE, 128 .bDescriptorType = USB_DT_ENDPOINT, 129 130 .bmAttributes = USB_ENDPOINT_XFER_BULK, 131 .wMaxPacketSize = cpu_to_le16(1024), 132 }; 133 134 static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = { 135 .bLength = USB_DT_SS_EP_COMP_SIZE, 136 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 137 .bMaxBurst = 0, 138 .bmAttributes = 0, 139 .wBytesPerInterval = 0, 140 }; 141 142 static struct usb_descriptor_header *ss_loopback_descs[] = { 143 (struct usb_descriptor_header *) &loopback_intf, 144 (struct usb_descriptor_header *) &ss_loop_source_desc, 145 (struct usb_descriptor_header *) &ss_loop_source_comp_desc, 146 (struct usb_descriptor_header *) &ss_loop_sink_desc, 147 (struct usb_descriptor_header *) &ss_loop_sink_comp_desc, 148 NULL, 149 }; 150 151 /* function-specific strings: */ 152 153 static struct usb_string strings_loopback[] = { 154 [0].s = "loop input to output", 155 { } /* end of list */ 156 }; 157 158 static struct usb_gadget_strings stringtab_loop = { 159 .language = 0x0409, /* en-us */ 160 .strings = strings_loopback, 161 }; 162 163 static struct usb_gadget_strings *loopback_strings[] = { 164 &stringtab_loop, 165 NULL, 166 }; 167 168 /*-------------------------------------------------------------------------*/ 169 170 static int loopback_bind(struct usb_configuration *c, struct usb_function *f) 171 { 172 struct usb_composite_dev *cdev = c->cdev; 173 struct f_loopback *loop = func_to_loop(f); 174 int id; 175 int ret; 176 177 /* allocate interface ID(s) */ 178 id = usb_interface_id(c, f); 179 if (id < 0) 180 return id; 181 loopback_intf.bInterfaceNumber = id; 182 183 id = usb_string_id(cdev); 184 if (id < 0) 185 return id; 186 strings_loopback[0].id = id; 187 loopback_intf.iInterface = id; 188 189 /* allocate endpoints */ 190 191 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc); 192 if (!loop->in_ep) { 193 autoconf_fail: 194 ERROR(cdev, "%s: can't autoconfigure on %s\n", 195 f->name, cdev->gadget->name); 196 return -ENODEV; 197 } 198 199 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc); 200 if (!loop->out_ep) 201 goto autoconf_fail; 202 203 /* support high speed hardware */ 204 hs_loop_source_desc.bEndpointAddress = 205 fs_loop_source_desc.bEndpointAddress; 206 hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress; 207 208 /* support super speed hardware */ 209 ss_loop_source_desc.bEndpointAddress = 210 fs_loop_source_desc.bEndpointAddress; 211 ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress; 212 213 ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs, 214 ss_loopback_descs); 215 if (ret) 216 return ret; 217 218 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n", 219 (gadget_is_superspeed(c->cdev->gadget) ? "super" : 220 (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")), 221 f->name, loop->in_ep->name, loop->out_ep->name); 222 return 0; 223 } 224 225 static void lb_free_func(struct usb_function *f) 226 { 227 struct f_lb_opts *opts; 228 229 opts = container_of(f->fi, struct f_lb_opts, func_inst); 230 231 mutex_lock(&opts->lock); 232 opts->refcnt--; 233 mutex_unlock(&opts->lock); 234 235 usb_free_all_descriptors(f); 236 kfree(func_to_loop(f)); 237 } 238 239 static void loopback_complete(struct usb_ep *ep, struct usb_request *req) 240 { 241 struct f_loopback *loop = ep->driver_data; 242 struct usb_composite_dev *cdev = loop->function.config->cdev; 243 int status = req->status; 244 245 switch (status) { 246 247 case 0: /* normal completion? */ 248 if (ep == loop->out_ep) { 249 req->zero = (req->actual < req->length); 250 req->length = req->actual; 251 } 252 253 /* queue the buffer for some later OUT packet */ 254 req->length = loop->buflen; 255 status = usb_ep_queue(ep, req, GFP_ATOMIC); 256 if (status == 0) 257 return; 258 259 /* "should never get here" */ 260 /* FALLTHROUGH */ 261 262 default: 263 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name, 264 status, req->actual, req->length); 265 /* FALLTHROUGH */ 266 267 /* NOTE: since this driver doesn't maintain an explicit record 268 * of requests it submitted (just maintains qlen count), we 269 * rely on the hardware driver to clean up on disconnect or 270 * endpoint disable. 271 */ 272 case -ECONNABORTED: /* hardware forced ep reset */ 273 case -ECONNRESET: /* request dequeued */ 274 case -ESHUTDOWN: /* disconnect from host */ 275 free_ep_req(ep, req); 276 return; 277 } 278 } 279 280 static void disable_loopback(struct f_loopback *loop) 281 { 282 struct usb_composite_dev *cdev; 283 284 cdev = loop->function.config->cdev; 285 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL); 286 VDBG(cdev, "%s disabled\n", loop->function.name); 287 } 288 289 static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len) 290 { 291 struct f_loopback *loop = ep->driver_data; 292 293 return alloc_ep_req(ep, len, loop->buflen); 294 } 295 296 static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop, 297 struct usb_ep *ep) 298 { 299 struct usb_request *req; 300 unsigned i; 301 int result; 302 303 /* 304 * one endpoint writes data back IN to the host while another endpoint 305 * just reads OUT packets 306 */ 307 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep); 308 if (result) 309 goto fail0; 310 result = usb_ep_enable(ep); 311 if (result < 0) 312 goto fail0; 313 ep->driver_data = loop; 314 315 /* 316 * allocate a bunch of read buffers and queue them all at once. 317 * we buffer at most 'qlen' transfers; fewer if any need more 318 * than 'buflen' bytes each. 319 */ 320 for (i = 0; i < loop->qlen && result == 0; i++) { 321 req = lb_alloc_ep_req(ep, 0); 322 if (!req) 323 goto fail1; 324 325 req->complete = loopback_complete; 326 result = usb_ep_queue(ep, req, GFP_ATOMIC); 327 if (result) { 328 ERROR(cdev, "%s queue req --> %d\n", 329 ep->name, result); 330 goto fail1; 331 } 332 } 333 334 return 0; 335 336 fail1: 337 usb_ep_disable(ep); 338 339 fail0: 340 return result; 341 } 342 343 static int 344 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop) 345 { 346 int result = 0; 347 348 result = enable_endpoint(cdev, loop, loop->in_ep); 349 if (result) 350 return result; 351 352 result = enable_endpoint(cdev, loop, loop->out_ep); 353 if (result) 354 return result; 355 356 DBG(cdev, "%s enabled\n", loop->function.name); 357 return result; 358 } 359 360 static int loopback_set_alt(struct usb_function *f, 361 unsigned intf, unsigned alt) 362 { 363 struct f_loopback *loop = func_to_loop(f); 364 struct usb_composite_dev *cdev = f->config->cdev; 365 366 /* we know alt is zero */ 367 disable_loopback(loop); 368 return enable_loopback(cdev, loop); 369 } 370 371 static void loopback_disable(struct usb_function *f) 372 { 373 struct f_loopback *loop = func_to_loop(f); 374 375 disable_loopback(loop); 376 } 377 378 static struct usb_function *loopback_alloc(struct usb_function_instance *fi) 379 { 380 struct f_loopback *loop; 381 struct f_lb_opts *lb_opts; 382 383 loop = kzalloc(sizeof *loop, GFP_KERNEL); 384 if (!loop) 385 return ERR_PTR(-ENOMEM); 386 387 lb_opts = container_of(fi, struct f_lb_opts, func_inst); 388 389 mutex_lock(&lb_opts->lock); 390 lb_opts->refcnt++; 391 mutex_unlock(&lb_opts->lock); 392 393 loop->buflen = lb_opts->bulk_buflen; 394 loop->qlen = lb_opts->qlen; 395 if (!loop->qlen) 396 loop->qlen = 32; 397 398 loop->function.name = "loopback"; 399 loop->function.bind = loopback_bind; 400 loop->function.set_alt = loopback_set_alt; 401 loop->function.disable = loopback_disable; 402 loop->function.strings = loopback_strings; 403 404 loop->function.free_func = lb_free_func; 405 406 return &loop->function; 407 } 408 409 static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item) 410 { 411 return container_of(to_config_group(item), struct f_lb_opts, 412 func_inst.group); 413 } 414 415 CONFIGFS_ATTR_STRUCT(f_lb_opts); 416 CONFIGFS_ATTR_OPS(f_lb_opts); 417 418 static void lb_attr_release(struct config_item *item) 419 { 420 struct f_lb_opts *lb_opts = to_f_lb_opts(item); 421 422 usb_put_function_instance(&lb_opts->func_inst); 423 } 424 425 static struct configfs_item_operations lb_item_ops = { 426 .release = lb_attr_release, 427 .show_attribute = f_lb_opts_attr_show, 428 .store_attribute = f_lb_opts_attr_store, 429 }; 430 431 static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page) 432 { 433 int result; 434 435 mutex_lock(&opts->lock); 436 result = sprintf(page, "%d\n", opts->qlen); 437 mutex_unlock(&opts->lock); 438 439 return result; 440 } 441 442 static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts, 443 const char *page, size_t len) 444 { 445 int ret; 446 u32 num; 447 448 mutex_lock(&opts->lock); 449 if (opts->refcnt) { 450 ret = -EBUSY; 451 goto end; 452 } 453 454 ret = kstrtou32(page, 0, &num); 455 if (ret) 456 goto end; 457 458 opts->qlen = num; 459 ret = len; 460 end: 461 mutex_unlock(&opts->lock); 462 return ret; 463 } 464 465 static struct f_lb_opts_attribute f_lb_opts_qlen = 466 __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR, 467 f_lb_opts_qlen_show, 468 f_lb_opts_qlen_store); 469 470 static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page) 471 { 472 int result; 473 474 mutex_lock(&opts->lock); 475 result = sprintf(page, "%d\n", opts->bulk_buflen); 476 mutex_unlock(&opts->lock); 477 478 return result; 479 } 480 481 static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts, 482 const char *page, size_t len) 483 { 484 int ret; 485 u32 num; 486 487 mutex_lock(&opts->lock); 488 if (opts->refcnt) { 489 ret = -EBUSY; 490 goto end; 491 } 492 493 ret = kstrtou32(page, 0, &num); 494 if (ret) 495 goto end; 496 497 opts->bulk_buflen = num; 498 ret = len; 499 end: 500 mutex_unlock(&opts->lock); 501 return ret; 502 } 503 504 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen = 505 __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR, 506 f_lb_opts_bulk_buflen_show, 507 f_lb_opts_bulk_buflen_store); 508 509 static struct configfs_attribute *lb_attrs[] = { 510 &f_lb_opts_qlen.attr, 511 &f_lb_opts_bulk_buflen.attr, 512 NULL, 513 }; 514 515 static struct config_item_type lb_func_type = { 516 .ct_item_ops = &lb_item_ops, 517 .ct_attrs = lb_attrs, 518 .ct_owner = THIS_MODULE, 519 }; 520 521 static void lb_free_instance(struct usb_function_instance *fi) 522 { 523 struct f_lb_opts *lb_opts; 524 525 lb_opts = container_of(fi, struct f_lb_opts, func_inst); 526 kfree(lb_opts); 527 } 528 529 static struct usb_function_instance *loopback_alloc_instance(void) 530 { 531 struct f_lb_opts *lb_opts; 532 533 lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL); 534 if (!lb_opts) 535 return ERR_PTR(-ENOMEM); 536 mutex_init(&lb_opts->lock); 537 lb_opts->func_inst.free_func_inst = lb_free_instance; 538 lb_opts->bulk_buflen = GZERO_BULK_BUFLEN; 539 lb_opts->qlen = GZERO_QLEN; 540 541 config_group_init_type_name(&lb_opts->func_inst.group, "", 542 &lb_func_type); 543 544 return &lb_opts->func_inst; 545 } 546 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc); 547 548 int __init lb_modinit(void) 549 { 550 int ret; 551 552 ret = usb_function_register(&Loopbackusb_func); 553 if (ret) 554 return ret; 555 return ret; 556 } 557 void __exit lb_modexit(void) 558 { 559 usb_function_unregister(&Loopbackusb_func); 560 } 561 562 MODULE_LICENSE("GPL"); 563